1. Field of the Invention
The present invention relates generally to orthopedic devices for the stabilization and control of a human knee joint that has been injured. More particularly, the invention relates to an orthopedic knee brace having an adjustable knee pad support that enables a wearer or medical professional to quickly and efficiently adjust the lateral corrective force placed on the knee joint by the support, thereby permitting control of the joint so as to optimize healing and stability.
2. Description of the Related Art
Orthopedic knee braces are commonly worn by patients after surgery for treatment of an injury to the knee joint. Knee braces generally serve dual purposes: first, the brace stabilizes the joint in order to control its lateral movement. Second, they limit joint flexion and/or extension in an adjustable and controllable manner to prevent recurrence of injury to the knee.
A knee brace of the initially mentioned type is disclosed in one of the present inventors U.S. Pat. No. 5,259,832, which discloses a multiaxis controlled knee brace utilizing a four bar joint mechanism and lateral and medial support pads for maintaining proper position of the knee brace when worn by the wearer. However, this design fails to provide for the independent adjustment of the support pads relative to the knee joint for providing stability to the knee joint. The use of orthopedic knee braces having adjustable support members is conventional within the prior art. Such an arrangement provides the knee brace with medial and/or lateral support pads that are positioned proximate to and in engagement with the medial and lateral sides of the knee joint to provide comfort and support to the wearer by stabilizing the knee joint against lateral movement.
The effectiveness of providing lateral stabilization to the knee joint is largely dependent upon the position of the pad. Incorrect or poor positioning of the knee brace, in particular the support pad, could result in the exacerbation of the existing knee injury by destabilizing the knee joint. Consequently, there have been many attempts to solve this problem by providing the knee brace with means for adjusting the lateral position of the support pads independent of the knee brace. However, certain shortcomings have been encountered with regard to the use of the conventional knee brace designs.
For example, U.S. Pat. No. 5,807,294 to Cawley et al. discloses a lateral support assembly for an osteoarthritic knee brace that utilizes an adjustable screw design to laterally adjust the position of a condylar pad member relative the knee joint. However, this design provides for adjusting the pad by using a tool to rotatably adjust the screw members, which requires that the tool be readily available to the wearer during times in which he or she must readjust the setting of the pad assembly and the need to separately adjust two screws complicates the adjustment process. In addition, in cases where the wearer flexed and extended their leg, the screws continued to independently adjust the support pad.
U.S. Pat. No. 4,940,045 to Cromartie discloses an adjustable medial condylar support pad affixed to a plate hingedly connected to an upper longitudinal rib within a medial side member of a knee brace. The support pad is manually adjusted by rotating a spacer member about a pivot point located above the support pad. While this device allows for the hand-held adjustment of the support pad, it does not provide for ease in adjustment since the spacer member is awkwardly positioned between the support pad and longitudinal rib. Furthermore, the hinge arrangement causes the support pad to be increasingly inclined relative to the knee joint as it is adjusted inward.
Accordingly, there is still a need for a lateral support device for an orthopedic knee brace that allows for simple and effective adjustment of the support pad in correcting the lateral force of the support pad on the knee joint. There also is a need for a support device that allows the wearer to quickly and easily adjust the device by hand when the knee brace is not fitted on the his or her leg.
In view of the foregoing, it is an object of the present invention to provide a lateral support device for an orthopedic knee brace that can be quickly adjusted to obtain the optimum degree of corrective force on the knee joint.
It is a further object of the present invention to provide a lateral support device for an orthopedic knee brace that will prevent any potential change in correction once it has been set. These and other objects and characteristics of the present invention are achieved in accordance with a preferred embodiment, which provides an orthopedic knee brace having a pair of femoral and tibial links and a hinge mechanism by which lateral side and medial side femoral links are pivotally connected to lateral side and medial side tibial links respectively. The knee brace also includes an adjustable knee pad support fixedly positioned on the lateral and medial sides of the knee joint, and a spring-loaded ratchet mechanism featuring a series of interlocking teeth that allows for the horizontal displacement of the pad support. This spring loaded design is an advantageous feature since it prevents any unintended change in correction force supplied by the pad supports. Moreover, in an effort to provide greater flexibility to the wearer in and enhance the stabilization of the design, the knee brace is designed such that the pad supports are mounted for rotation about a point on the axis of the femoral condyle of the knee joint. The knee pad support may be adjusted by hand by merely rotating the ratchet mechanism to achieve the proper correction or with an adjusting tool that engages a plurality of notches surrounding the periphery of the ratchet mechanism. During adjustment of the condylar pad, there is an audible click as the teeth engage in each subsequent position. The audible clicks enable it to be known how far the condylar pad has been laterally displaced toward the knee joint in an effort to increase the corrective force placed on the joint. In the fully extended setting, the condylar pad may extend for distances up to {fraction (3/16)} of an inch from its original setting. The adjustability feature enables the wearer or medical professional to increase correction at least by an additional 1 to 5 degrees beyond the natural correction built into the knee brace. To decrease the corrective force, the ratchet mechanism is rotated past the last set of teeth and the condylar pad will be biased back to its original position by the spring.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the detailed drawings which show, for purposes of illustration only, a single preferred embodiment of the present invention.